High levels of 3-mono- and 3,5-diiodotyrosine (MIT and DIT, respectively) in urine have been related to iodotyrosine dehalogenase 1 deficiency, a type of congenital hypothyroidism. However, the ...determination of MIT and DIT in urine is not included in newborn screening programs performed in clinical laboratories to detect inborn errors of metabolism. We report here on the development of an analytical method for the determination of MIT and DIT in newborn urine and dried urine spots (DUS) by Liquid Chromatography Isotope Dilution tandem Mass Spectrometry (LC-IDMSMS). The development included the synthesis of
N-monoiodotyrosine and
C
-diiodotyrosine through the iodination of
N-tyrosine and
C
-tyrosine, respectively, using bis(pyridine)iodonium(I) tetrafluoroborate (IPy
BF
). Both labelled analogues were added at the beginning of the sample preparation procedure and used to develop both single- and double-spike LC-IDMS methods for the determination of MIT and DIT. The developed double spike methodology was able to quantify and correct possible MIT ↔ DIT interconversions throughout the sample preparation, which was observed for concentrated urine samples but not for DUS. Suppression matrix effects on the absolute signals of MIT and DIT were observed in urine samples but did not affect the IDMS results as recoveries on urine samples at different dilution factors could be considered quantitative. Method detection limits were 0.018 and 0.046 ng g
(limits of quantification 0.06 and 0.15 ng g
) by single-spike IDMS, for MIT and DIT, respectively, in the analysis of urine samples and 0.07 and 0.05 ng g
(limits of quantification 0.23 and 0.17 ng g
) for MIT and DIT, respectively, in the analysis of DUS. No significant differences were obtained for MIT concentrations in the analysis of the same newborn samples stored as liquid urine or DUS when the results were corrected for the creatinine content. Finally, 36 DUS samples from healthy newborns were analyzed and MIT was detected in all samples at low ng mg
creatinine levels.
Hepatorenal tyrosinaemia (Tyr 1) is a rare inborn error of tyrosine metabolism. Without treatment, patients are at high risk of developing acute liver failure, renal dysfunction and in the long run ...hepatocellular carcinoma. The aim of our study was to collect cross-sectional data.
Via questionnaires we collected retrospective data of 168 patients with Tyr 1 from 21 centres (Europe, Turkey and Israel) about diagnosis, treatment, monitoring and outcome. In a subsequent consensus workshop, we discussed data and clinical implications.
Early treatment by NTBC accompanied by diet is essential to prevent serious complications such as liver failure, hepatocellular carcinoma and renal disease. As patients may remain initially asymptomatic or develop uncharacteristic clinical symptoms in the first months of life newborn mass screening using succinylacetone (SA) as a screening parameter in dried blood is mandatory for early diagnosis. NTBC-treatment has to be combined with natural protein restriction supplemented with essential amino acids. NTBC dosage should be reduced to the minimal dose allowing metabolic control, once daily dosing may be an option in older children and adults in order to increase compliance. Metabolic control is judged by SA (below detection limit) in dried blood or urine, plasma tyrosine (<400 μM) and NTBC-levels in the therapeutic range (20-40 μM). Side effects of NTBC are mild and often transient. Indications for liver transplantation are hepatocellular carcinoma or failure to respond to NTBC. Follow-up procedures should include liver and kidney function tests, tumor markers and imaging, ophthalmological examination, blood count, psychomotor and intelligence testing as well as therapeutic monitoring (SA, tyrosine, NTBC in blood).
Based on the data from 21 centres treating 168 patients we were able to characterize current practice and clinical experience in Tyr 1. This information could form the basis for clinical practice recommendations, however further prospective data are required to underpin some of the recommendations.
Newborn Screening Programs (NSP) in Spain were born in the
city of Granada in 1968. Till the 1980s, they were developed around
the so-called “National Plan for Preventing Subnormality”, covering
up ...to 30% of the Spanish newborns. From 1982, when the health
system management was transferred to the different autonomous regions,
the NSP began to expand, and the bases to transform them into
an organized and multidisciplinary activity, integrated and coordinated
from the National Health System were settled. Despite this expansion,
it is not until the 1990s when their coverage reaches almost
100% newborns in Spain.
NSP grew up asymmetrically across the different autonomous
regions. In 2005 and 2006 the scientific societies SEQC (Spanish
Society of Clinical Chemistry) and AECNE (Spanish Society of
Newborn Screening), coordinated by the Health Promotion Area of
the General Directorate of Public Health, gathered together the necessary
information to elaborate a report on the NSP in Spain addressed
to the Interterritorial Council of the National Health System. In July
2013, that Council approved the seven diseases that should be part of
each region newborn screening panel, being the first step towards the
NSP harmonization in Spain. Currently, the NSP include between 8
and 29 diseases in their panels, thus more still more efforts are needed
in order to achieve a higher uniformity.
Los Programas de Cribado Neonatal (PCN) nacen en España en
Granada en el año 1968. Posteriormente, y hasta los años 80, se fueron
desarrollando en torno al llamado “Plan Nacional de Prevención
de la Subnormalidad” con una cobertura cercana al 30% de los recién
nacidos españoles. A partir de 1982, con el inicio de la gestión de
la sanidad a las comunidades autónomas (CCAA), los PCN se expandieron
y se comenzaron a sentar las bases para que éstos se convirtieran
en una actividad organizada y multidisciplinar, integrados y
coordinados desde el Sistema de Salud. A pesar de dicha expansión
no es hasta el inicio de la década de los 90 cuando se consigue una
cobertura próxima al 100% de los RN en España.
Los PCN fueron creciendo de forma muy asimétrica en las diferentes
CCAA y en los años 2005 y 2006 las Sociedades Científicas
SEQC (Sociedad Española de Química Clínica) y AECNE
(Asociación Española de Cribado Neonatal), con la coordinación
del Área de Promoción de la Salud de la Dirección General de Salud
Pública, recopilaron la información y elaboraron un informe, sobre
los PCN en España para el Consejo Interterritorial del sistema
Nacional de Salud (CISNS). En julio de 2013 este Consejo aprobó
las siete enfermedades que debían formar parte del panel de detección
de los PCN territoriales, primer paso hacia la armonización de
estos programas. Actualmente, los PCN incluyen entre 8 y 29 enfermedades
por lo que es necesario seguir trabajando para conseguir una
mayor uniformidad.
Background
Nitisinone is used to treat hereditary tyrosinemia type 1 (HT‐1) by preventing accumulation of toxic metabolites, including succinylacetone (SA). Accurate quantification of SA during ...newborn screening is essential, as is quantification of both SA and nitisinone for disease monitoring and optimization of treatment. Analysis of dried blood spots (DBS) rather than plasma samples is a convenient method, but interlaboratory differences and comparability of DBS to serum/plasma may be issues to consider.
Methods
Eight laboratories with experience in newborn screening and/or monitoring of patients with HT‐1 across Europe participated in this study to assess variability and improve SA and nitisinone concentration measurements from DBS by liquid chromatography‐tandem mass spectrometry (LC‐MS/MS). Quantification of nitisinone from both DBS and plasma was performed to assess sample comparability. In addition, efforts to harmonize laboratory procedures of SA and nitisinone quantifications during 5 rounds of analysis are described.
Results
Nitisinone levels measured from DBS and plasma strongly correlated (R2 = 0.93). Due to partitioning of nitisinone to the plasma, levels were higher in plasma by a factor of 2.34. In the initial assessment of laboratory performance, all had linear calibrations of SA and nitisinone although there was large inter‐laboratory variability in actual concentration measurements. Subsequent analytical rounds demonstrated markedly improved spread and precision over previous rounds, an outcome confirmed in a final re‐test round.
Conclusion
The study provides guidance for the determination of nitisinone and SA from DBS and the interpretation of results in the clinic. Inter‐laboratory analytical harmonization was demonstrated through calibration improvements.
Galician newborn screening program for early
detection of endocrine and metabolic diseases
began in 1978 and was a pioneer in expanded
newborn screening in Spain with the incorporation
of mass ...spectrometry in July 2000. As a primary
objective, 28 diseases are screened, including those
recommended SNS except sickle cell anemia which
is in the inclusion phase.
In its 20-year history, 404,616 newborns (nb)
have been analyzed, identifying 547 cases affected
by the diseases included, with a global incidence of
1: 739 newborns and 1: 1.237 of the screened inborn
errors of metabolism (IEM) (1:1.580 nb if excluding
benign hyperphenylalaninemia-HPA), with an
average participation of 99.35%, progressively
higher during the analyzed period. Among the
pathologies screened, congenital hypothyroidism
(1:2.211 nb), cystinuria (1:4.129 nb) and HPA
(1:5.699 nb), followed by phenylketonuria and cystic
fibrosis (1:10,936 nb) stand out for their incidence.
Sixty-six cases of false positives were identified
(seventeen of them in relation to maternal pathology)
and five false negatives, being the overall PPV
and NPV of the program respectively of 89.2%
and 99.99%, with a sensitivity of 99.09% and
a specificity of 99.98%. The mortality rate of
diagnosed CME patients is 1.52%, with eleven cases
presenting symptoms prior to the screening result
(2%). The intelligence quotient of IEM patients at
risk of neurological involvement is normal in more
than 95% of cases.
El Programa Gallego para la Detección Precoz de
Enfermedades Endocrinas y Metabólicas se inició en
1978 y fue pionero en España en el cribado neonatal
ampliado con la incorporación de la espectrometría
de masas en julio de 2000. Como objetivo primario
se criban veintiocho enfermedades, incluyendo las
de la cartera básica del Servicio Nacional de Salud
excepto la anemia de células falciformes, que está en
fase de inclusión.
En sus veinte años de trayectoria se analizaron
404.616 recién nacidos (RN), identificando 547
casos afectos de las enfermedades incluidas, con
una incidencia global de 1:739 RN vivos y de
1:1.237 RN de las enfermedades metabólicas
congénitas (EMC) cribadas (1:1.580 RN excluyendo
la hiperfenilalaninemia benigna-HPA), con una
participación media del 99,35%, progresivamente
creciente durante el período analizado. Entre las
patologías cribadas destacan por su incidencia el
hipotirodismo congénito (1:2.211 RN), la cistinuria
(1:4.129 RN) y la HPA (1:5.699 RN), seguida de
fenilcetonuria y fibrosis quística (1:10.936 RN).
Se identificaron sesenta y seis casos de falsos
positivos (diecisiete de los mismos en relación con
patología materna) y cinco falsos negativos, siendo
el VPP (valor predictivo positivo) y el VPN (valor
predictivo negativo) global del programa del 89,2%
y 99,99%, respectivamente, con una sensibilidad
de 99,09% y una especificidad del 99,98%. La
tasa de mortalidad de los pacientes con EMC
diagnosticados fue del 1,52%, presentando once
casos sintomatología previa al resultado del cribado
(2%). El cociente intelectual de los pacientes con
EMC y riesgo de afectación neurológica es normal
en más del 95% de los casos.
A study on selenium levels has been carried out in human placenta, maternal and umbilical cord blood, hair and nails of a group of 50 mothers and in the hair of the newborns. The determinations were ...perfomed by electrothermal atomic absorption spectrometry.
The selenium concentration obtained for each sample type was as follows: For the human placenta the values obtained were between 0.56 and 1.06
μg/g (mean±standard deviation: 0.81±0.02
μg/g). The levels for the umbilical cord blood were 51.1–104.2
μg/l (76.3±6.5
μg/l). For the maternal blood the values measured were between 57.3 and 117.9
μg/l (90.0±15.2
μg/l), and for hair and nails were 0.22–1.5
μg/g (0.60±0.37
μg/g) and 0.46–1.57
μg/g (0.90±0.27
μg/g), respectively. For the hair of the newborns the values obtained were between 0.40 and 2.53
μg/g (1.04±0.48
μg/g).
The effect of different variables as age, habitat, nutritional index or gestation age of the mothers on the selenium concentration in the samples was studied. The influence of the habitat is significant with a confidence level of 95% for the selenium concentration in maternal blood and umbilical cord blood samples. The influence of the mothers’ age is significant with a confidence level of 95% for the selenium concentration in the umbilical cord blood samples. For the placenta samples, the effect of the nutritional index is significant with a confidence level of 95%.
There is a positive correlation between samples of umbilical cord blood and the newborns’ hair, between placenta and umbilical cord, and between cord blood and maternal blood.
Galician newborn screening program for early detection of endocrine and metabolic diseases began in 1978 and was a pioneer in expanded newborn screening in Spain with the incorporation of mass ...spectrometry in July 2000. As a primary objective, 28 diseases are screened, including those recommended SNS except sickle cell anemia which is in the inclusion phase. In its 20-year history, 404,616 newborns (nb) have been analyzed, identifying 547 cases affected by the diseases included, with a global incidence of 1: 739 newborns and 1: 1.237 of the screened inborn errors of metabolism (IEM) (1:1.580 nb if excluding benign hyperphenylalaninemia-HPA), with an average participation of 99.35%, progressively higher during the analyzed period. Among the pathologies screened, congenital hypothyroidism (1:2.211 nb), cystinuria (1:4.129 nb) and HPA (1:5.699 nb), followed by phenylketonuria and cystic fibrosis (1:10,936 nb) stand out for their incidence. Sixty-six cases of false positives were identified (seventeen of them in relation to maternal pathology) and five false negatives, being the overall PPV and NPV of the program respectively of 89.2% and 99.99%, with a sensitivity of 99.09% and a specificity of 99.98%. The mortality rate of diagnosed CME patients is 1.52%, with eleven cases presenting symptoms prior to the screening result (2%). The intelligence quotient of IEM patients at risk of neurological involvement is normal in more than 95% of cases.
Newborn Screening Programs (NSP) in Spain were born in the city of Granada in 1968. Till the 1980s, they were developed around the so-called "National Plan for Preventing Subnormality", covering up ...to 30% of the Spanish newborns. From 1982, when the health system management was transferred to the different autonomous regions, the NSP began to expand, and the bases to transform them into an organized and multidisciplinary activity, integrated and coordinated from the National Health System were settled. Despite this expansion, it is not until the 1990s when their coverage reaches almost 100% newborns in Spain. NSP grew up asymmetrically across the different autonomous regions. In 2005 and 2006 the scientific societies SEQC (Spanish Society of Clinical Chemistry) and AECNE (Spanish Society of Newborn Screening), coordinated by the Health Promotion Area of the General Directorate of Public Health, gathered together the necessary information to elaborate a report on the NSP in Spain addressed to the Interterritorial Council of the National Health System. In July 2013, that Council approved the seven diseases that should be part of each region newborn screening panel, being the first step towards the NSP harmonization in Spain. Currently, the NSP include between 8 and 29 diseases in their panels, thus more still more efforts are needed in order to achieve a higher uniformity.
Background: We analyzed the main factors associated with intravenous thrombolysis (IVT) in patients with minor ischemic stroke. Methods: Data were obtained from a prospective, government-mandated, ...population-based registry of stroke code patients in Catalonia (6 Comprehensive Stroke Centers, 8 Primary Stroke Centers, and 14 TeleStroke Centers). We selected patients diagnosed with ischemic stroke and National Institutes of Health Stroke Scale (NIHSS) ≤5 at hospital admission from January 2016 to December 2020. We excluded patients with a baseline modified Rankin Scale score of ≥3, absolute contraindication for IVT, unknown stroke onset, or admitted to hospital beyond 4.5 after stroke onset. The main outcome was treatment with IVT. We performed univariable and binary logistic regression analyses to identify the most important factors associated with IVT. Results: We included 2975 code strokes; 1433 (48.2%) received IVT of which 30 (2.1%) had a symptomatic hemorrhagic transformation. Patients treated with IVT as compared to patients who did not receive IVT were more frequently women, had higher NIHSS, arrived earlier to hospital, were admitted to a Comprehensive Stroke Centers, and had large vessel occlusion. After binary logistic regression, NIHSS score 4 to 5 (odds ratio, 40.62 95% CI, 31.73–57.22; P <0.001) and large vessel occlusion (odds ratio, 16.39 95% CI, 7.25–37.04; P <0.001) were the strongest predictors of IVT. Younger age, female sex, baseline modified Rankin Scale score of 0, earlier arrival to hospital (<120 minutes after stroke onset), and the type of stroke center were also independently associated with IVT. The weight of large vessel occlusion on IVT was higher in patients with lower NIHSS. Conclusions: Minor stroke female patients, with higher NIHSS, arriving earlier to the hospital, presenting with large vessel occlusion and admitted to a Comprehensive Stroke Centers were more likely to receive intravenous thrombolysis.
Background: Hepatorenal tyrosinaemia (Tyr 1) is a rare inborn error of tyrosine metabolism. Without treatment, patients are at high risk of developing acute liver failure, renal dysfunction and in ...the long run hepatocellular carcinoma. The aim of our study was to collect cross-sectional data. Methods: Via questionnaires we collected retrospective data of 168 patients with Tyr 1 from 21 centres (Europe, Turkey and Israel) about diagnosis, treatment, monitoring and outcome. In a subsequent consensus workshop, we discussed data and clinical implications. Results: Early treatment by NTBC accompanied by diet is essential to prevent serious complications such as liver failure, hepatocellular carcinoma and renal disease. As patients may remain initially asymptomatic or develop uncharacteristic clinical symptoms in the first months of life newborn mass screening using succinylacetone (SA) as a screening parameter in dried blood is mandatory for early diagnosis. NTBC-treatment has to be combined with natural protein restriction supplemented with essential amino acids. NTBC dosage should be reduced to the minimal dose allowing metabolic control, once daily dosing may be an option in older children and adults in order to increase compliance. Metabolic control is judged by SA (below detection limit) in dried blood or urine, plasma tyrosine (<400 mu M) and NTBC-levels in the therapeutic range (20-40 mu M). Side effects of NTBC are mild and often transient. Indications for liver transplantation are hepatocellular carcinoma or failure to respond to NTBC. Follow-up procedures should include liver and kidney function tests, tumor markers and imaging, ophthalmological examination, blood count, psychomotor and intelligence testing as well as therapeutic monitoring (SA, tyrosine, NTBC in blood). Conclusion: Based on the data from 21 centres treating 168 patients we were able to characterize current practice and clinical experience in Tyr 1. This information could form the basis for clinical practice recommendations, however further prospective data are required to underpin some of the recommendations.
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